UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Non-working Commodore PET 3016

SiriusHardware · 8th Mar 2021, 11:27 pm

Ah, it's all a question of units. (Some day you'll have to explain to me how you get that 'Omega' character - I don't seem to have one on my keyboard).

You do occasionally get some apparently impossible or unlikely voltage readings. (If there really is zero ohms between those two points then there is no way for the voltages on them to be different, because they are directly connected together). Let's not worry about that for now. We should be able to make a bit more progress when your replacement UH6 etc. arrive.

With the new UH6 fitted look for activity on pins 2 and 3 of UH6, you should see 500KHz waveforms on both of those.

If you do have those, then look for activity on the outputs of UH9 pins 12, 9, 8, 11.

Let us know how that goes.

8th Mar 2021, 11:27 pm	#838
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,579	Re: Non-working Commodore PET 3016 Ah, it's all a question of units. (Some day you'll have to explain to me how you get that 'Omega' character - I don't seem to have one on my keyboard). You do occasionally get some apparently impossible or unlikely voltage readings. (If there really is zero ohms between those two points then there is no way for the voltages on them to be different, because they are directly connected together). Let's not worry about that for now. We should be able to make a bit more progress when your replacement UH6 etc. arrive. With the new UH6 fitted look for activity on pins 2 and 3 of UH6, you should see 500KHz waveforms on both of those. If you do have those, then look for activity on the outputs of UH9 pins 12, 9, 8, 11. Let us know how that goes.